The façade of a building plays a central role in a building's environmental performance, influencing energy usage by determining how light, heat and air are exchanged with its surroundings. As one example, the interlocking systems that comprise curtain walls for high-rise buildings: structural, glazing, insulation, ventilation and shading, all play a role in managing the energy flows between interior and exterior.
One key strategy to achieve sustainable performance is for buildings to actively adapt and respond to changing climatic conditions. This strategy may be applied to facades in different ways. For example, an adaptive façade may have operable elements such as shades that extend and retract automatically. Those devices can respond to environmental data (i.e. temperature, light intensity and wind flow) gathered from sensors, and, utilizing computational intelligence, the building can optimize its environmental configuration for different environmental conditions.
This concept of a responsive facade has been termed “intelligent skin” indicating the analogy with natural systems.
A significant portion of the façade is comprised of windows—or more generally, glazed areas. Static methods are often used to set the light transmissivity of glass. Ceramic fritting is widely utilized where a graphic pattern is applied to glass in order to block some light transmission, yet still allowing sufficient transparency for viewing. However, standard ceramic fritting is static and does not respond to changing conditions.
By integrating responsive controls with fritted glass surfaces, improved light control and decreased energy usage can be achieved.
An adaptive window could, for example, allow solar gain during cold weather, yet block the sun when it is warm. Natural light within the building can be maintained at desirable levels. Controllable transparency can also be used to allow visual contact when needed, yet provide privacy under other circumstances.
Beyond transparency control, a physical surface that can adjust its permeability, thereby controlling the passage of air, moisture or heat, provides additional benefits. Utilizing an exterior layer having controllable permeability, energy from the environment may be accepted or blocked as needed.
Currently, such adaptive control within the facade is achieved with standard products such as blinds, shades or curtains. Beyond traditional devices, a new generation of adaptive glass technology is available such as ‘switchable’ and ‘electrochromic’ glass. However, these technologies have not received wide acceptance to date.
The invention disclosed herein provides new methods to provide surfaces having controllable properties. Such properties include transparency, permeability and acoustic performance. Surfaces that are formulated according to the disclosed invention may then be integrated into building façades as an ‘adaptive layer’ providing enhanced environmental performance.